Abstract: An apparatus for loading workpieces without exposure of a work chamber to the atmosphere comprises a transfer chamber formed in part by an inner plate section which serves as a cover plate with an inner port therethrough to the work chamber. An entry plate section has an entry port therethrough to the atmosphere, is spaced laterally from the inner port and has a door. A plurality of tubular loading members are equally spaced arcuately in a wheel member mounted in the transfer chamber. Each loading member is displaceable at a loading site between a normal position in the wheel in which each loading member is relocatable laterally by the wheel, and a sealed position proximate the entry port. A seal between the entry plate section and the loading member in its sealed position allows access of a workpiece to the loading cylinder through the entry port without exposing the remainder of the transfer chamber to the atmosphere.